Rotary pump



Dec. 14 1926.

W. l. DERRICK ROTARY PUMP Filed May 4, 1922 3 L w n I m M r w. w I w 6 1i J F 0 w 2 r! 'P ientlibe 14, 1926.

WILLIAM I. DERRICK, OF DAVENPORT,

IOWA, ASSIGNOR TO WESTCO-CHIPPEWA PUMP COMPANY, OF DAVENPORT,-IOWA, ACORPORATION OF DELAWARE.

ROTARY PUMP.

Application filed May 4,

This invention relates to rotary pumps, and more particularly totheclass of pumps employing a rotor in a housing.

An object of this invention 18 to provlde a pump with a rotor which,when the pump is operating and building up pressure, Wlll' automaticallybalance itself axially so that it will not bear on the casing and conseuently will reduce Wear and lengthen the life of the pump.

In' pumps of the type wherein a rotor engages water in an annularpassage the rotor has a more or less close working fit between portionsof the opposite walls of the casing in which it is mounted, which isnecessary to cut off any substantial communication between the annularpassage and the central portion of the chamber formed by the casingwalls. A small amount of liquid, however, will Work through betweenthe'rotor and side walls, and if, due to imperfect fit, a greater amountof liquid escapes to the center of the chamber on one side of the rotorthan the other, an excess pressure is built up upon that side tending topush the rotor still farther toward one wall of the faces have arelatively large contact, so that accurate ositioning of the casingwalls and rotor wit respect to each other is possible. Other objectswill be apparent from the 1 following description in connection with theannexed drawings.

In said annexed drawings, Figure 1 is an elevation partially broken awayto show a portion of the rotor and casing in section.v

Fig. 2 is a central transverse vertical section showing the coverdetached.

Fig. 3 is a view of the rotor. Fig. 4: is a section on an axial planethrough the rotor.

Fig. 5 is a side elevation of the casing.

tion.

1922. Serial No. 558,452.

Fig. 6 is an enlarged view of that portion pjf the rotor and casingshown in section in- Referring to the drawing, the casing body 1., base2, and shaft supporting bracket? are cast integrally. The casing 1 issaucer shaped and has a peripheral rim 4. having a flat peripheral sideface 5, an internal peripheral channel 6, the outer wall of which may beformed by an inwardly extending rib 7 having a cylindrical inner edge.The web portion of the casing body has upon the inner face thereof arelatively low annular rib 8 concentric with the rim 4:. The casing body1 has an axial integral tubular boss 9 on the outer side thereof. Thebracket 3 has a threaded bearing aperture 10 in axial alinement with theboss 9. The casing cover 11 has its inner face circumferentiallyrabbeted to provide a. cylindrical shoulder 12 to fit within thecylindrical inner edge of the rib 7, and a flat inner peripheral portion13 outside the shoulder 12 to fit against the flat face 5 of the casingbody 1. The contiguous faces 5 and 13 of the casing body and cover maybe provided with registermg grooves preferably greater in onedimensioncross sectionally than the other, thus forming an annularpacking chamber 14 to receive an annular packing member 25. The member25 is preferably circular in cross section but may be of any desiredcross sectional shape, it being necessary only that the cross sectionaldimension of the packing in the direction of the axis of the pump beslightly larger than the cross sectional dimension of the chamber 1 1 inthe same direc- It will thus be seen that when the cover is tightlyfitted to the casing body the packing tightly engages both the cover andthe casing body and may be compressed and deformed throughout the lengthof the chamber 14, thus insuring a tight engagement between the packingand casing and cover throughout the circumference of the packing. Byhaving the clamber 14 of greater dimension in one direc ion crosssectionally, room is provided to contain the deformed packing so thatthe contiguous faces 5 and 13 of the cover and pump body may be insuredof a metal to metal contact, thus insuring also an accurate fitting ofthe easing walls with respect to the rotor. Concentric with the shoulder12, the cover 11 I in the web 19 of the rotor.

abutment to the inlet.

has upon its'inner face a relatively low annular rib 15 of the samediameter as the opposed rib 8 of the casing body.

By way of example the rotor casing herein disclosed is one having ribsbetween which the rotor has ,a close working fit and rotates. It is tobe understood, however, that the ribs may be mounted upon the rotor andthewalls of the casing be straight, so that in eifect there is producedan outer annular water passage, in which the water is engaged by. theblades or buckets of a rotor. Working fit between the rotating memberand the casing, otherwise relatively high pressures cannot be built upin such passage, for it would short circuit from the discharge orpressure end of the passage directly to the suction or inlet end of thepassage. However, the clearance between the rotor and the casing may bevaried somewhat depending upon the conditions and purposes of the pump.The preferred construction is that herein shown, in which the ribs aremounted on the casing walls and the rotor has a portion engaging betweenthe ribs, for in this case the rotor which is the moving part has lessweight and also has less surface to be engaged by the pressure of thewater in the fluid channel, and conse quently less pressure istransmitted to the bearings.

A shaft 16 is journaled axially in the casing body and cover and inbearing members mounted in the tubular boss 9 and in the aperture 10 inthe bracket 3. A rotor 17 is fixed to the shaft 16 within the casing.The rotor 17 is a circular disk having a hub 18, a web 19 and an outerthickened peripheral portion 20 upon the outer edges of which are formedthe impeller teeth 21. Relatively large apertures 22 are formed Thethickened portion 20 of the rotor has a close working fit between theannular ribs 8. and 15 of the casing body 1 and cover 11 whereby theperipheral portion of the casing-is substantially cut off from thecentral portion thereof. The outlet and inlet connections communicatewith the peripheral portion of the casing and an abutment 23 between theinlet and outlet closes the passage outside the periphery of the rotorbetween the inlet and outlet and has a close fit over the rotor outsidethe ribs 8 and 15. The abutment is thick enough to fitover a pluralityof the peripheral teeth of the rotor, whereby pressure generated at thedischarge outlet cannot be released by escape of water past the A slightclearance between the ribs 8 and 15 and the rotor 12 is necessary topermit rotation of the rotor; this-slight clearance will be sufiicienteven with the closest working fit to permit a relatively slight leakageto the center of the There must be a relatively close casing in the formof a thin film of liquid which acts as a lubricant between the surfacesof the rotor and ribs. The clearance may be varied in the diilerentsides and designs of'pumps for various purposes but it is desirable toequalize whatever pressures are created on the sides of the rotor toprevent the rotor from being forced axially in one direction or theother. If there is a slight misahnement betweenthe rotor and casing, agreater leakage will occur on one side of the rotor than-the other,which would tend to buildup a pressure on. he side where the leakage isgreater, which increase the misalinement. By providing the largeapertures 22 in the web the pressure is equalized on the opposite sidesof the thatto make the channel relatively small,

as disclosed herein, a considerably higher ould tend to pressure canbeproduced with my pump and still a good volume of water can bedelivered.

Furthermore, it is to be understood that the particular forms ofapparatus shown and described, and the particular procedure set forth,are presented for the purposes of.

explanation and illustration, and that various modifications of saidapparatus and procedure can be made Without de arting from my invention,as designed in t e appended claims.

hat I claim is:

1. In a rotary pump acasing, a shaft mounted in said casing for rotarymovement therein and carrying a rotor, an outer annular passage formedin said casing by said rotor and thecasing walls, bladeson said rotorengaging the water in said outer annular passage, said passageconforming in cross sectional shape to the cross sectional shape of theperiphery of the rotor and having its walls disposed relatively close tothe rotor, said rotor having a material part of its web portion cut awayto permit flow of water from one side to the other to equalize thepressure on opposite sides thereof.

2. In a rotary pump a casing, a shaft mounted to rotate in the'casingwalls, a rotor carried by said shaft, said rotor comprising a diskhaving a web portion and blades around the periphery, annular ribsextending from the walls of the casing on each side of the rotor andforming together with the rotor an outer annular water passage, saidpassage being relatively small and having inlet and discharge ports anda partition between said ports, said rotor having perforawater to passfreely, from one sideto the other when the rotor is rotating- I 3; In arotary pump a casing forming a rotor chamber, of a rotor. mounted insaid casing, said rotor having a shorter diameter than said chamber, theside walls of said casing having opposed annular ribs in closeengagement with opposite sides of said rotor adjacent the peripherythereof, whereby a peripheral passage for liquid is formedcircumferentially of said rotor, the walls of said passage beingrelatively close to the peripheral faces and edge of said rotor andsubstantially parallel'therewith, said ribs coact ing with said rotor toprevent any substantial leakage from said outer passage to the centralportion of said chamber, said rotor, having a substantial part of itsweb within said'ribs removed to permit ready flow of liquid from oneside of the rotor to the other to equalize the pressure on oppositesides of said rotor.

4. In a rotary pump, the combination with a casing having a shallowcylindrical rotor chamber therein, said chamber bein closed except forperipheral inlet. and outlet passages, of a disk rotor in said casing,said rotor bein of shorter diameter, than said chamber, t e side wallsof said chamber having inwardly extending annular ribs in close towardthe periphery thereof, whereby a pcripheral passage is formed which issubstantially closed from thecentral portion of said casing, said sidewalls of said'chamber being tions of suflicient size in its web to..perinit l engagementiwith opposite faces of said disk" disposedrelatively closeto the-faces of the rotor, said disk having asubstantial portion of-lts body within said annular ribs cut away topermit ready flow of liquid from one side of the rotor to the other toequalize the pressure on opposite sides of said rotor.' 5. In a rotarypump, a narrow cylindrical rotor chamber, a disk rotor therein havingperipheral blades and being of less diameter than said chamber, thesidewalls of said chamber having annular ribs'of less diameter than therotor between which said rotor has a close ,workin fit, whereby acircumferem.

tial assa'ge is tormed at the .outer periphery of t e chamber, inlet andoutlet conduits communicating with said circumferential considerablyreater than the cross sectional area ofthe circumferential passageinsaid rotor chamber.

In testimony whereof, I hereunto aifix my signature.

" j L'DERltIGK,

